Now that Boston boy toy Sam Adams has blown onto hip-hop’s front lines, there’s almost room for original frat rapper Asher Roth to find a respectable position somewhere between the big-indie Atmosphere types and the upper echelon of major-label boom-bap. Skillwise, the bony Pennsylvania whiteboy is not far from subterranean lyrical miracle status, and he can certainly out-rhyme all but the elite Hova-Ludacris caliber of commercial MCs. But he has to graduate on his own terms, and that’s why it’s unfortunate that he’s filled this mixtape with a slew of predictable mainstream fodder from the likes of Kanye West, Pharrell, and (gulp) Will.I.Am. As he smacks lips all over instrumentals like Saigon’s “C’Mon Baby,” the kid sounds as bored with his beats (and content) as hip-hop heads are sure to be with these selections. There’s still hope for Roth, but dude needs to mature on the microphone. For all that he’s comfortable juggling cheap sex metaphors on “Vagitables” — and slaying a Madlib slab on “Muddy Swim Trunks” — he mostly seems unaware of the creative possibilities that lie in the outer throes of hip-hop. He’d better discover some viable alternative textures soon, too, since his co-ed fan base has already moved on, and hood cats never liked him in the first place.